Friday, September 7, 2012Lake Erie's algae crisis part two: The urban factorOverflows from city sweage systems is part of the reason for the presence of algae in Lake ErieStory by KAREN SCHAEFER

Next week Cleveland will host hundreds of scientists, environmental advocates, and public officials gathering to discuss new and ongoing threats to the Great Lakes – from Asian carp to toxic hotspots. Great Lakes Week also will focus on blue-green algae that can kill fish, make people sick, and wreak havoc for tourism. Yesterday, independent producer Karen Schaefer reported on what scientists agree is the main source of the algae problem – farms. Today she examines another major source – cities.

This summer’s drought has kept Lake Erie largely free from toxic algae blooms. With less rain came less runoff from row crops along the Maumee and other rivers that feed into the lake. That farmland runoff carries phosphorus contained in manure and fertilizer. It’s phosphorous that feeds the growth of algae. The lack of rain and storms also meant no big overflows of sewage – that’s the other major source of Lake Erie phosphorus.

In fact, a study last year by scientists at the U.S. Geological Survey concluded that sewage from municipal plants in Detroit, Toledo and other cities along Lake Erie contribute almost as much phosphorus to the lake as farms. Dale Robertson is the lead author of that study.

“I think my study is showing that they’re both important. They might, on an individual day, individual season, they could vary. But, when you’re looking at this, there’s a lot of nutrients coming in from both of those sources.”

The USGS study has sparked some controversy. Ohio-based scientists, who for years have looked at the lake’s algae/phosphorus problem, believe the study is flawed when it comes to determining the source of the algae blooms. Pete Richards is a water quality scientist from Heidelberg University in Tiffin. He says you have to look at the concentrations of phosphorous, not just the amounts.

“Because the concentrations of phosphorous in the Detroit River plume are so much lower, you just can’t grow much algae in a given volume of water without running out of nutrients. You can grow ten to twenty times – and maybe even more – in the same volume of water in a typical Maumee River plume.”

Richards also says satellite images make it clear that it’s the mouth of the Maumee – not the Detroit River – where algae blooms form.

To some, the degree of responsibility that’s pinned on farms or the cities doesn’t matter. They just want to make sure we don’t have a repeat of the kind of algae outbreak we did in 2011.

Last fall, the floating mat of toxic algae blanketing large parts of Lake Erie was so thick it slowed down boats as they carved their way through, leaving behind brilliant green wakes. Steve Connor says it was the worst he’s ever seen. Connor is a charter boat captain in who’s been fishing on Lake Erie for more than forty years.

“When you take a body of water that, because of this algae problem, turns into a slimy, green-looking body of water, nobody really wants to come out here and say, well, that’s really attractive to go fishing in.”

The sport fishing industry, beach resorts, amusement parks – all took a hit from the 2011 algae outbreak. Connor says cities …not just farms…have to do more to stay on top of it.

Overflows from sewage systems that collect storm water and waste water are a fairly regular occurrence in Cleveland, Toledo, Detroit and other communities around the lake. And it’s a huge cost to fix it.

“I feel very saddened for the Detroit area, because of the financial hardships that they are suffering. Cleveland, they’re suffering. Toledo, fortunately, was under that billion dollar mark.”

That’s George Robinson, who’s directing Toledo’s 20-year project to separate the city’s storms sewers from its sanitary sewers. He’s grateful that its only costing a half billion dollars. But he’s also concerned about Detroit’s sewage treatment plant – the largest in the Great Lakes – which last year dumped 7-billion gallons of sewage and storm water into the lake. Officials there are still struggling over how to finance sewer upgrades without overburdening residents. In Cleveland, sewer rates are going up as much as 75-percent. That’s one reason cities are also now eying lower-cost green infrastructure projects to keep storm water and sewage out of Lake Erie.

“At the low end of the project, there’s only one set of catch basins, whereas normally we’d have maybe six catch basins along here.”

In the flood-prone neighborhood of Maywood, the city of Toledo has turned one street into a test of green infrastructure. Engineer Andy Langenderfer says the city spent 7-hundred thousand dollars to disconnect storm sewers, build permeable sidewalks, and turn tree lawns into water collectors, called bioswales. Langenderfer is standing on the once grassy strip between sidewalk and street that now dips to a shallow trench filled with blooming plants.

“You’re seeing the top if the bioswale. But actually the trench is down a good five feet. So it’s a mix of gravel and different types of soil mixtures, trying to slow down that runoff to the actual storm sewers.”

So far, Langenderfer says bioswales are reducing runoff by up to 70-percent in the one neighborhood where they’ve been tried. The city is looking to replicate similar green infrastructure projects, but cautions they won’t replace the need for more expensive hard infrastructure solutions. Still, scientists say every little bit helps in the fight to curb the phosphorus that’s feeding Lake Erie’s harmful algae blooms.

Listener Comments:

In 2011, there were 45 billion gallons of sewage overflows from the Detroit wasetwater plant of which 3 billion gallons was raw sewage. Also, the Detroit wastewater treatment plant was discharging sewage sludge(they make 500 tons per day) in the Detroit and Roughe Rivers and Lake Erie. From July 1, 2010 thru June 30, 2011, this amounted too 21,852 tons. The sludege was put in the rivers because only two of the 14 incenerators were working. The dumping of the sludge into the water was ongoing from 2009. In 2012 8 of the 14 incenerators are supposedly working.
In the 1970's and 1980's there was extensive lakewide monitoring by federal and state governments and universities.
There is a huge need for this now to know if the problem is getting better or worse and to find and reduce the largest sources of phosphorous loading.Posted by: Sandy (Lake Erie) on September 7, 2012 1:09AM